Cache.php clearOld is currently cleaning up all directories/files in the tempDir.
If mpdf is using the global tempdir (/tmp) this will clean up files of any other application using the global tempdir.

Error message if Mpdf is trying to clean up a file of another application:
unlink(/tmp/...): Operation not permitted
Cache.php: 95

I assume it is suggested to use a a dedicated mpdf tempDir

The image at the top of the README seems to be missing:

I found an image for Stringy on another site.
Can this be used, or is there a better one?
https://hotexamples.com/i/libraries#stringy

Tooltips shown in the wrong locations. It seems like conversion from 2D screen mouse cursor coordinates to character index within the internal data is wrong somewhere.

Create documentation for the wordacc program with:

1. name
2. synopsis
3. description
4. options
5. examples

Create the documentation in docs/wordacc.md and link to it from README.md!

Addresses #6.